As those skilled in the field of educational robotics are aware, most of the available tutorial or educational robots available on the market is a single configuration device such that the educational advantage therein is limited primarily to teaching how to program and thus control a robot arm. Since technical education will more and more include courses in robotics, with emphasis on all fields of robot kinematics, dynamics, design, programming, and applications, the single configuration units will simply lack the versatility, flexibility and thoroughness to which students should have access. To applicant's knowledge, none of the known devices utilizes modular, interchangeable parts which enable one to construct robots of from two through five articulations or axes.
No attempt will be made here to discuss the differences in the several types of robot anatomy or construction. Whether they are limited sequences robots, playback robots with point-to-point control or playback robots with continuous path control is of no concern within this patent application. Essentially, however, robots used for educational purposes are of the playback type with point-to-point control and thus there is required knowledge on the part of the control programmer that when the robot is commanded to move from one position to another, there could be involved independent operation of two or more of its articulations. The only information which the robot receives from its controls is to be taught the attitude of the limbs at the start of the move and the new attitude of those limbs when the particular move has been finished. While making the move as rapidly as it can, and while moving all limbs simultaneously if required to fulfill the given command, there is no definition of the paths which the robot limbs will trace. Thus, the control is point-to-point allowing some flexibility in the program control by which the various points are reached.
Various types of robot geometry are available depending upon the application or needs. As those skilled in the art are aware, the robot, depending on its mechanical design, may operate to mathematical advantage in (1) Cartesian coordinates, (2) Cylindrical coordinates, (3) Polar coordinates, or (4) Combinations thereof. Each of these configurations offers a different shape to the robots envelope volume or sphere of influence. Again, for different applications, different configurations may be appropriate and software can make possible transformations from one coordinate system to another. In every case, the arm carries a wrist assembly to orient its end effector as demanded by the application or goal in mind.
It is not uncommon for the wrist of the robot arm to provide three articulations or motions labeled pitch, yaw and roll. It will be noted that the various arm coordinate systems require three articulations to deliver the wrist assembly anywhere in the sphere of influence or envelope. It then requires three more articulations in the wrist for univeral orientation of the end effector. However, and quite often, robots are able to cope with job assignments without employing a full set of six articulations. Generally, five articulations are adequate since, for instance, yaw articulation in the end effector may not be necessary.
Among the prior art are four U.S. patents, none of which is seen upon close analysis to be material to the instant invention and thus are only of interest. They are U.S. Pat. Nos. 3,888,362; 3,066,805; 4,068,763; and 4,109,398. Applicant knows of no other pertinent or material references.